Main Regions and Quality Identification

Classic texts and trade experience favor leeches from several provinces, but quality still depends on species, catch time, processing, and storage. Different regions produce slightly different sizes and shapes — the broad-body leech tends to be larger, the Japanese medical leech smaller. Good Shui Zhi is dark brown or gray-brown, with clear segments, hard, glossy on the break, and a faint fishy smell; processed pieces are pale-yellow to brown-yellow, crisp, and mild-smelling. The common look-alikes are other segmented worms — check the shape and texture.

1. Main Use 1: Breaking Blood Stasis

(1) Traditional action: driving out old, stuck blood and unblocking the qi and blood it traps. (2) Typical patterns: stasis masses, stopped menses, and bruises from falls — fixed painful lumps, menses that will not come, clotted flow, swelling that will not fade after injury. (3) Usual pairings: Tao Ren (peach kernel), Hong Hua (safflower), San Leng (sparganium), and E Zhu (zedoary) to strengthen the stasis work. (4) Not for self-use: pregnancy, heavy periods, or no stasis-excess pattern at all.

2. Main Use 2: Freeing the Channels and Dispersing Masses

(1) Traditional action: unblocking the channels and dispersing the masses stasis builds. (2) Typical patterns: irregular periods, postpartum stasis cramping, and abdominal masses — a late period, dark-clotted flow, a lower belly that aches at touch after birth, a mass that can be felt. (3) Usual pairings: Dang Gui (angelica), Chuan Xiong (cnidium), and Chi Shao (peony root) to nourish and move blood — so the breaking does not drain the upright qi. (4) Not for self-use: pregnancy, heavy periods, or qi-blood weakness.

3. A Classic Pairing

Shui Zhi pairs classically with Tao Ren: the leech breaks stasis as its lead, and the peach kernel moves blood and moistens the intestines as the partner. Together they strengthen the stasis-breaking, channel-freeing work — for stasis-blocked stopped menses and masses. This pair belongs to a practitioner's pattern diagnosis, never self-pairing.

1. What They Share

• Both break blood stasis as a main action.
• Both are used for stasis masses, stopped menses, and bruises.
• Both demand constitution and dose care — pregnancy and no-stasis patterns are both cautions.

2. Key Differences

Nature and flavor: Shui Zhi is salty, bitter, and neutral with mild toxicity; Meng Chong is bitter and slightly cold with mild toxicity — the fly's nature is a little colder and its toxicity a little fiercer. Focus: Shui Zhi is stronger at freeing the menses, breaking stasis, and dispersing masses — for stopped menses and belly masses; Meng Chong is stronger at breaking stasis and dispersing knots — for bruises and stasis swelling, with a fiercer push. Tendency: both drain and break, but Shui Zhi also walks the liver channels while breaking; Meng Chong attacks the stasis more directly, with a simpler qi effect. Best fit: Shui Zhi for stasis stopped menses, postpartum stasis pain, and belly masses; Meng Chong for stasis swelling from falls and stubborn stasis accumulations. Who should avoid: Shui Zhi is off for pregnancy, heavy periods, and qi-blood weakness; Meng Chong adds a cold weak spleen-stomach to the list — its cold can harm the spleen-stomach yang. Where you meet them: Shui Zhi in gynecologic stasis formulas; Meng Chong more in injury formulas as a stasis-breaking partner, with stronger force.

3. One-Line Takeaway

In short, Shui Zhi frees the menses, breaks stasis, and disperses masses; Meng Chong breaks stasis and disperses knots with more force. Both can appear in stasis patterns — but they are not stand-ins for each other.

1. Home Stew

Example — Shui Zhi lean-meat stew: processed Shui Zhi 3 g (a medicinal piece under a practitioner's direction), lean pork 100 g, fresh ginger 2 slices — the pork washed and cut, stewed double-boiled with the leech and ginger for 1.5 hours, salted to taste. Fit: a stasis-leaning body — a dull complexion, skin bruising, a late clotted period. Not for: pregnancy, heavy periods, or no stasis pattern at all. Frequency: once a month, never frequent. Shui Zhi is a medicinal piece, not ordinary food — no casual daily use.

2. Decoction and Processing Differences

The raw leech is harder, more toxic, and difficult to grind — clinical use is almost always the processed form. At home, wrap the pieces in a cloth bag and decoct with the other herbs — never throw them straight into the pot. Different forms cannot be converted directly — a food-use amount is never a prescription dose.

3. Dosage and How Long to Use

The classic range is 1.5–3 g, adjusted after processing under strict professional direction. Food-use amounts are smaller and only for support — never for medicinal work. Not for long continuous use — the drain harms the upright qi; once a month at most for food use. Special groups ask a practitioner or pharmacist first — no self-deciding on dose or course.